£12m striker Berahino had gone 913 days without finding the back of the net, but his 53rd-minute header at the bet365 Stadium ended his goal-drought. It was also Berahino’s first Stoke goal since joining on a five-and-a-half-year deal in January last year and his first goal in 48 matches.
How Stoke fans rejoiced as the Potters prevented the Terriers from claiming their first win over them since March 1998.
Winger James McClean rattled the bar with a fierce drive and Berahino was well-placed to head home from close range to break his long-standing hoodoo.
And in the final minute of stoppage-time debutant Bacuna shanked his attempted clearance into his own net.
Stoke manager Gary Rowett had made four changes to his Championship side ahead of the visit of their higher-ranked opponents Huddersfield.
Goalkeeper Adam Federici, defender Ashley Williams, Congo forward Benik Afobe and midfielder – and captain for the night – Darren Fletcher all started for the Potters.
Town manager David Wagner made five changes to his team following their goalless draw with Cardiff on Saturday.
There were debuts for summer signings Erik Durm and Bacuna, while Danny Williams and Elias Kachunga made their first appearances of the season.
Isaac Mbenza, a substitute in Saturday’s goalless draw with the Bluebirds, made his first start for the visitors.
Berahinomade the breakthrough in the 53rd minute after some great work from McLean.
His left-foot rocket rattled the bar and Berahino was perfectly placed to nod home. To rub salt into Town’s wounds Bacuna’s awful attempted clearance gave goalkeeper Jonas Lossl no chance.
Stoke City: Federici, Martina, Williams, Martins Indi, Pieters (Bauer 78), Diouf (Krkic 64), Etebo, Fletcher, McClean, Berahino (Adam 85), Afobe. Unused substitutes: Allen, Campbell, Haugaard, Soutar.
Huddersfield Town: Lossl, Smith, Schindler, Stankovic, Durm (Lowe 77), Williams (Mooy 69), Bacuna, Kachunga, Mbenza, Sabiri (Pritchard 46), Depoitre. Unused substitutes: Diakhaby, Quaner, Jorgensen, Schofield.
Referee: Peter Bankes (Merseyside).